长期热老化下一种PBX的拉伸性能和蠕变性能（英文）

The Tensile Properties and Creep Performance of a Long-term Thermally Aged Plastic Bonded Explosive

利用单轴拉伸试验和数小时下的拉伸蠕变试验评定了在长期热老化下作用下某PBX的力学性能。试验用的哑铃型样品分别在45,55,65℃和75℃下贮存了36个月。拉伸试验在45℃下进行,贮存了6个月和36个月的样品的拉伸蠕变试验也在45℃下进行。结果显示,与原始样品相比,45℃下,样品的拉伸强度和拉伸模量在长期热老化后没有明显变化,但是除75℃下的老化样品,其余样品的蠕变断裂时间均大大延长。通过扫描电镜观察并结合粘结剂的接触角分析,提出,在55℃以下,该PBX的力学失效是由热流变机制控制的,而高于55℃时,炸药晶体和粘结剂界面之间的热应力失配起到了关键作用。同时也表明,低于75℃下的长期贮存有助于改善PBX的蠕变性能,延长其蠕变断裂时间。

Uniaxial tensile testing and short-term tensile creep testing within several hours for a long-term thermally aged polymer bonded explosive （PBX） within years were conducted to evaluate the aging effects in terms of mechanical properties. Dumbbell specimens were thermally aged at 45, .55, 65 ℃ and 7.5 ℃ respectively for 36 months. The quasistatic tensile strength testing was conducted at 45 ℃. The tensile creep testing for 6 month and 36 month thermally stored specimens were carried out at controlled temperature of 4.5℃. The results show that the tensile mechanical properties, such as tensile strength and elastic modulus essentially keep unchanged compared to the pristine specimens, but the creep time to rupture （TTR） of the thermally treated specimen becomes much longer than the pristine specimens except for 75 ℃ . Combining scanning electronic microscope （SEM） observation and contacted angle analysis, we proposed that the mechanical failure for the targeted PBX was controlled by the thermal theological mechanism of the ingredients when aged temperature is below 55 ℃, but when temperature is above 55 ℃ ; the failure was controlled by thermal stresses mismatch around the interface between the binder and the explosive crystals in the formulation. The long-term thermally storage below 75℃ for this PBX can improve the creep performance in terms of TTR.